Gridded CO2 and CH4 Flux Estimates for pan-Arctic and Boreal Regions, 2003-2015

This dataset provides gridded estimates of gross primary productivity (GPP), ecosystem respiration (Reco), net ecosystem CO2 exchange (NEE = Reco - GPP), and methane (CH4) emissions from tundra and boreal wetland soils, across the pan-Arctic and Boreal zone (>49 degrees north) at 1-km spatial resolution. The data were produced through simulations of the Arctic Terrestrial Carbon Flux Model (TCFM-Arctic) and are provided at the daily time step for the years 2003-2015. TCFM-Arctic uses a light-use efficiency approach driven by satellite estimates of FPAR (fraction of absorbed photosynthetically active radiation) to estimate GPP, and autotrophic respiration (Rauto) is estimated as a fraction of GPP. Heterotrophic respiration (Rhetero) is estimated using decomposition rates with environmental constraints applied to three near-surface soil organic carbon (SOC) pools, and Reco is determined as the sum of Ra and Rh. Methane production is estimated using optimal CH4 production rates with environmental constraints applied to the labile carbon pool, and transfer of CH4 from the soil to the atmosphere is modeled through vegetation, soil diffusion, and water ebullition pathways. The model estimates were calibrated and evaluated using >60 tower eddy covariance (EC) sites. Baseline carbon pools were initialized by continuously cycling (spinning-up) the model for 1,000 model years using recent climatology from 1985 to 2002 to reach a dynamic steady-state between estimated net primary productivity (NPP = GPP - Rauto) and near-surface SOC pools. The TCFM-Arctic simulations were extended to the full Arctic-boreal domain at a 1-km spatial resolution using land cover maps representing high latitude vegetation communities. The data are provided in NetCDF and comma-separated values (CSV) formats.

本数据集提供了格网化的总初级生产力（GPP）、生态系统呼吸（Reco）、净生态系统二氧化碳交换（NEE = Reco - GPP）以及苔原和北方湿地土壤的甲烷（CH4）排放估计，覆盖了泛北极和北方地区（北纬49度以上）的1公里空间分辨率。数据通过模拟北极陆地碳通量模型（TCFM-Arctic）生成，并以每日时间步长提供2003-2015年的数据。TCFM-Arctic模型采用光能利用效率方法，通过卫星估算的叶面积指数（FPAR）来估计GPP，而自养呼吸（Rauto）则估计为GPP的分数。异养呼吸（Rhetero）通过应用环境约束到近地表土壤有机碳（SOC）三个库的分解速率来估计，而Reco则是Ra和Rh的和。甲烷的产生是通过应用环境约束到活性碳库的最佳CH4产生速率来估计的，甲烷从土壤到大气中的转移则通过植被、土壤扩散和水沸腾途径进行建模。模型估计值通过超过60个塔式涡度相关（EC）站点进行校准和评估。基线碳库通过连续循环（加速）模型1000个模型年，使用1985年至2002年的近期气候学数据，以实现估算的净初级生产力（NPP = GPP - Rauto）与近地表SOC库之间的动态稳态。TCFM-Arctic模拟扩展到了全北极-北方区域，空间分辨率为1公里，使用代表高纬度植被群落的土地覆盖图。数据以NetCDF和逗号分隔值（CSV）格式提供。